check engine GMC SIERRA 1500 2012 Service Manual

Black plate (30,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-30 Vehicle Care
Battery
If the vehicle is a Hybrid, see the
Hybrid Supplement for more
information.
This vehicle has a maintenance free
battery (or batteries). Refer to the
replacement number on the original
battery label when a new battery is
needed. SeeEngine Compartment
Overview on page 10‑6 for battery
location.
{WARNING
Battery posts, terminals, and
related accessories contain lead
and lead compounds, chemicals
known to the State of California to
cause cancer and reproductive
harm. Wash hands after handling.
Vehicle Storage
{WARNING
Batteries have acid that can burn
you and gas that can explode.
You can be badly hurt if you are
not careful. See Jump Starting on
page 10‑88 for tips on working
around a battery without
getting hurt.
Infrequent Usage: Remove the
black, negative (−) cable from the
battery to keep the battery from
running down.
Extended Storage: Remove the
black, negative (−) cable from the
battery or use a battery trickle
charger.
Four-Wheel Drive
Transfer Case
When to Check Lubricant
Refer to Maintenance Schedule on
page 11‑3 to determine when to
check the lubricant.
How to Check Lubricant
Electric Shift Transfer Case
A. Fill Plug
B. Drain Plug

Black plate (33,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-33
Also, if a vehicle has just been
driven before checking the fluid
level, it may appear lower than
normal because fluid has traveled
out along the axle tubes and has
not drained back to the sump
area. Therefore, a reading taken
five minutes after the vehicle has
been driven will appear to have a
lower fluid level than a vehicle that
has been stationary for an hour or
two. Remember that the rear axle
assembly must be supported to get
a true reading.How to Check Lubricant
2500HD with 6.0 L
All Other Series and EnginesTo get an accurate reading, the
vehicle should be on a level
surface.
.For all 4.3 L, 4.8 L and 5.3 L
1500 Series applications, the
proper level is 1.0 mm to
19.0 mm (0.04 in to 0.7 in)
below the bottom of the fill hole,
located on the rear axle. Add
only enough fluid to reach the
proper level.
.For all 6.0 L and 6.2 L
1500 Series applications, the
proper level is from 15 mm to
40 mm (0.6 in to 1.6 in) below
the bottom of the fill plug hole,
located on the rear axle. Add
only enough fluid to reach the
proper level.
.For all 6.0 L 2500HD Series
applications, the proper level is
from 0 mm to 13 mm (0 to 0.5 in)
below the bottom of the fill plug
hole, located on the rear axle.
Add only enough fluid to reach
the proper level.

Black plate (35,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-35
Starter Switch Check
{WARNING
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
1. Before starting this check, be sure there is enough room
around the vehicle.
2. Firmly apply both the parking brake and the regular brake.
See Parking Brake on
page 9‑54.
Do not use the accelerator
pedal, and be ready to turn off
the engine immediately if it
starts.
3. Try to start the engine in each gear. The vehicle should start
only in P (Park) or N (Neutral). If the vehicle starts in any other
position, contact your dealer for
service.Automatic Transmission
Shift Lock Control
Function Check
{WARNING
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
1. Before starting this check, be sure there is enough room
around the vehicle. It should be
parked on a level surface.
2. Firmly apply the parking brake. See Parking Brake on
page 9‑54.
Be ready to apply the regular
brake immediately if the vehicle
begins to move. 3. With the engine off, turn the
ignition on, but do not start the
engine. Without applying the
regular brake, try to move the
shift lever out of P (Park) with
normal effort. If the shift lever
moves out of P (Park), contact
your dealer for service.
Ignition Transmission
Lock Check
While parked, and with the parking
brake set, try to turn the ignition to
LOCK/OFF in each shift lever
position.
.The ignition should turn to
LOCK/OFF only when the shift
lever is in P (Park).
.The ignition key should come
out only in LOCK/OFF.
Contact your dealer if service is
required.

Black plate (36,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-36 Vehicle Care
Park Brake and P (Park)
Mechanism Check
{WARNING
When you are doing this check,
the vehicle could begin to move.
You or others could be injured
and property could be damaged.
Make sure there is room in front
of the vehicle in case it begins to
roll. Be ready to apply the regular
brake at once should the vehicle
begin to move.Park on a fairly steep hill, with the
vehicle facing downhill. Keeping
your foot on the regular brake, set
the parking brake.
.To check the parking brake's
holding ability: With the engine
running and the transmission in
N (Neutral), slowly remove foot
pressure from the regular brake
pedal. Do this until the vehicle is
held by the parking brake only.
.To check the P (Park)
mechanism's holding ability:
With the engine running, shift
to P (Park). Then release the
parking brake followed by the
regular brake.
Contact your dealer if service is
required.
Wiper Blade Replacement
Windshield wiper blades should be
inspected for wear or cracking.
See Maintenance Schedule on
page 11‑3 for more information on
wiper blade inspection.
Replacement blades come in
different types and are removed in
different ways. To remove the wiper
blade:
1. Pull the windshield wiper arm connector away from the
windshield.
2. Squeeze the grooved areas on
each side of the blade, and turn
the blade assembly away from
the arm connector.

Black plate (44,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-44 Vehicle Care
Headlamp Wiring
An electrical overload may cause
the lamps to go on and off, or in
some cases to remain off. Have
the headlamp wiring checked right
away if the lamps go on and off or
remain off.
Windshield Wipers
If the wiper motor overheats due to
heavy snow or ice, the windshield
wipers will stop until the motor cools
and will then restart.
Although the circuit is protected
from electrical overload, overload
due to heavy snow or ice may
cause wiper linkage damage.
Always clear ice and heavy snow
from the windshield before using the
windshield wipers.
If the overload is caused by an
electrical problem and not snow or
ice, be sure to get it fixed.
Fuses and Circuit
Breakers
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
The wiring circuits in the vehicle
are protected from short circuits
by a combination of fuses, circuit
breakers and fusible thermal links.
This greatly reduces the chance of
fires caused by electrical problems.
Look at the silver-colored band
inside the fuse. If the band is broken
or melted, replace the fuse. Be sure
you replace a bad fuse with a new
one of the identical size and rating.If you ever have a problem on the
road and don't have a spare fuse,
you can borrow one that has the
same amperage. Just pick some
feature of your vehicle that you can
get along without–
like the radio or
accessory power outlet– and use its
fuse, if it is the correct amperage.
Replace it as soon as you can.
Engine Compartment
Fuse Block
If the vehicle has a diesel engine,
see the Duramax Diesel supplement
for more information.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.

Black plate (88,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-88 Vehicle Care
Jump Starting
For more information about the
vehicle battery, seeBattery on
page 10‑30.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
If the vehicle's battery (or batteries)
has run down, you may want to use
another vehicle and some jumper
cables to start your vehicle. Be sure
to use the following steps to do it
safely.
{WARNING
Batteries can hurt you. They can
be dangerous because:
.They contain acid that can
burn you.
.They contain gas that can
explode or ignite.
.They contain enough
electricity to burn you.
If you do not follow these steps
exactly, some or all of these
things can hurt you. Notice:
Ignoring these steps
could result in costly damage to
the vehicle that would not be
covered by the warranty.
Trying to start the vehicle by
pushing or pulling it will not
work, and it could damage the
vehicle.
1. Check the other vehicle. It must
have a 12-volt battery with a
negative ground system.
Notice: Only use a vehicle that
has a 12-volt system with a
negative ground for jump
starting. If the other vehicle does
not have a 12-volt system with a
negative ground, both vehicles
can be damaged.
2. If you have a vehicle with a diesel engine with two batteries,
you should know before you
begin that, especially in cold
weather, you may not be able to

Black plate (91,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-91
{WARNING
Fans or other moving engine
parts can injure you badly. Keep
your hands away from moving
parts once the engine is running.
6. Check that the jumper cables do not have loose or missing
insulation. If they do, you could
get a shock. The vehicles could
be damaged too.
Before you connect the cables,
here are some basic things you
should know. Positive (+) will go
to positive (+) or to a remote
positive (+) terminal if the vehicle
has one. Negative (−) will go to a
heavy, unpainted metal engine
part or to a remote negative (−)
terminal if the vehicle has one. Do not connect positive (+) to
negative (−) or you will get a
short that would damage the
battery and maybe other parts
too. And do not connect the
negative (−) cable to the
negative (−) terminal on the
dead battery because this can
cause sparks.
5.3L Engine (4.3L, 4.8L, 6.0L, 6.2L
and 6.6L Similar)
7. Connect the red positive (+) cable to the positive (+) terminal
of the vehicle with the dead
battery. 8. Do not let the other end touch
metal. Connect it to the
positive (+) terminal of the
good battery. Use a remote
positive (+) terminal if the vehicle
has one.
9. Now connect the black negative (−) cable to the
negative (−) terminal of the
good battery. Use a remote
negative (−) terminal if the
vehicle has one.
Do not let the other end touch
anything until the next step.
10. Connect the other end of the negative (−) cable to a heavy,
unpainted metal engine part or
to the remote negative (−)
terminal, on the vehicle with
the dead battery.
11. Start the vehicle with the good battery and run the engine for a
while.

Black plate (1,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Service and Maintenance 11-1
Service and
Maintenance
General Information
General Information . . . . . . . . . . 11-1
Maintenance Schedule
Maintenance Schedule . . . . . . . 11-3
Special Application Services
Special ApplicationServices . . . . . . . . . . . . . . . . . . . . 11-8
Additional Maintenance
and Care
Additional Maintenanceand Care . . . . . . . . . . . . . . . . . . . 11-9
Recommended Fluids,
Lubricants, and Parts
Recommended Fluids andLubricants . . . . . . . . . . . . . . . . . 11-12
Maintenance Replacement Parts . . . . . . . . . . . . . . . . . . . . . . 11-15
Maintenance Records
Maintenance Records . . . . . . 11-16
General Information
This maintenance section applies to
vehicles with a gasoline engine. For
diesel engine vehicles, see the
maintenance schedule section in
the Duramax Diesel Supplement.
Your vehicle is an important
investment. This section describes
the required maintenance for the
vehicle. Follow this schedule to
help protect against major repair
expenses resulting from neglect or
inadequate maintenance. It may
also help to maintain the value of
the vehicle if it is sold. It is the
responsibility of the owner to have
all required maintenance performed.
Your dealer has trained
technicians who can perform
required maintenance using
genuine replacement parts.
They have up‐to‐date tools and
equipment for fast and accurate
diagnostics. Many dealers have
extended evening and Saturday hours, courtesy transportation, and
online scheduling to assist with
service needs.
Your dealer recognizes the
importance of providing
competitively priced maintenance
and repair services. With trained
technicians, the dealer is the place
for routine maintenance such as oil
changes and tire rotations and
additional maintenance items like
tires, brakes, batteries, and wiper
blades.
Notice:
Damage caused by
improper maintenance can lead to
costly repairs and may not be
covered by the vehicle warranty.
Maintenance intervals, checks,
inspections, recommended fluids,
and lubricants are important to
keep the vehicle in good working
condition.
The Tire Rotation and Required
Services are the responsibility of the
vehicle owner. It is recommended to
have your dealer perform these
services every 12 000 km/7,500 mi.

Black plate (3,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Service and Maintenance 11-3
Maintenance
Schedule
Owner Checks and Services
At Each Fuel Stop
.Check the engine oil level. See
Engine Oil on page 10‑7.
Once a Month
.Check the tire inflation
pressures. See Tire Pressure on
page 10‑58.
.Inspect the tires for wear. See
Tire Inspection on page 10‑65.
.Check the windshield washer
fluid level. See Washer Fluid on
page 10‑26.
Engine Oil Change
When the CHANGE ENGINE OIL
SOON message displays, have the
engine oil and filter changed within
the next 1 000 km/600 mi. If driven
under the best conditions, the
engine oil life system might not
indicate the need for vehicle service for more than a year. The engine oil
and filter must be changed at least
once a year and the oil life system
must be reset. Your trained dealer
technician can perform this work.
If the engine oil life system is reset
accidentally, service the vehicle
within 5 000 km/3,000 mi since
the last service. Reset the oil life
system when the oil is changed.
See
Engine Oil Life System on
page 10‑10.
Tire Rotation and Required
Services Every 12 000 km/
7,500 mi
Rotate the tires, if recommended
for the vehicle, and perform the
following services. See Tire
Rotation on page 10‑65.
.Check engine oil level and oil
life percentage. If needed,
change engine oil and filter, and
reset oil life system. See Engine
Oil on page 10‑7 andEngine Oil
Life System on page 10‑10.
.Check engine coolant level. See
Engine Coolant on page 10‑19.
.Check windshield washer fluid
level. See Washer Fluid on
page 10‑26.
.Visually inspect windshield
wiper blades for wear, cracking,
or contamination. See Exterior
Care on page 10‑98. Replace
worn or damaged wiper blades.
See Wiper Blade Replacement
on page 10‑36.
.Check tire inflation pressures.
See Tire Pressure on
page 10‑58.
.Inspect tire wear. See Tire
Inspection on page 10‑65.
.Visually check for fluid leaks.
.Inspect engine air cleaner filter.
See Engine Air Cleaner/Filter on
page 10‑17.
.Inspect brake system.

Black plate (9,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Service and Maintenance 11-9
Additional
Maintenance and Care
Your vehicle is an important
investment and caring for it
properly may help to avoid
future costly repairs. To maintain
vehicle performance, additional
maintenance services may be
required. It is recommended
that your dealer perform these
services—their trained dealer
technicians know your vehicle
best. Your dealer can also
perform a thorough assessment
with a multi‐point inspection to
recommend when your vehicle may
need attention. The following list is
intended to explain the services
and conditions to look for that may
indicate services are required. Battery
The battery supplies power to
start the engine and operate any
additional electrical accessories.
.To avoid break‐down or failure
to start the vehicle, maintain a
battery with full cranking power.
.Trained dealer technicians have
the diagnostic equipment to test
the battery and ensure that the
connections and cables are
corrosion‐free.
Belts
.Belts may need replacing if
they squeak or show signs of
cracking or splitting.
.Trained dealer technicians
can inspect the belts and
recommend replacement when
necessary. Brakes
Brakes stop the vehicle and are
crucial to safe driving.
.Signs of brake wear may include
chirping, grinding, or squealing
noises, or difficulty stopping.
.Trained dealer technicians have
access to tools and equipment
to inspect the brakes and
recommend quality parts
engineered for the vehicle.
Fluids
Proper fluid levels and approved
fluids protect the vehicle’s
systems and components. See
Recommended Fluids and
Lubricants on page 11‑12 for GM
approved fluids.
.Engine oil and windshield
washer fluid levels should be
checked at every fuel fill.
.Instrument cluster lights may
come on to indicate that fluids
may be low and need to be
filled.